Retinal diseases are common, difficult to diagnose and track and can have very serious consequences. For example, macular degeneration is a very serious eye disease that affects up to roughly 20% of the elderly population and is the leading cause of blindness in the developed world. Many other retinal diseases such as glaucoma and diabetic retinopathy also affect large numbers of persons and can lead to serious loss of vision function. Due to the very serious nature of these diseases, it is highly regrettable that low cost and highly effective screening and disease tracking systems are not available. Today, the onset of retinal disease is very often first detected by patients noticing vision loss in their daily activity. Otherwise, paper grids referred to as Amsler grids are also used to provide a rudimentary low-cost screening tool. However, very often by the time it has been detected and diagnosed, considerable vision function has been lost and cannot be recovered. Additionally, changes in vision function for patients already diagnosed with retinal disease can signal the need for more aggressive or even emergency treatment. Hence, a low cost and effective system for screening for retinal disease and tracking retinal function is highly desirable. Accordingly, it is clear that vision function testing techniques to enable highly effective retinal function testing and other vision function testing are highly desirable.
Fortunately, computer graphics and gaming technology has now advanced to the level that low cost, highly effective devices for vision function testing and tracking can be envisioned. Binocular viewers allow each eye to be measured or trained independently or together, advances in variable optics allow for changes in focus to be accommodated, computer generated graphics allow interesting static and dynamic images to be created and low cost human input devices allow user feedback information to be collected easily concerning how a user is reacting to the given images.